Heating apparatus



Filed July 26, 1941 2 Sheets-Sheet 1 NEY 2 fled w A March 16, 1943. B. GOERG HEATING ABPARATUS Filed July 26, 1941 2 Sheets-Sheet 2 II? 4J\' II I! 5447 n 95 I67 ,5/ ll 3/ E 6556 L 2 r 66 J4 55 m. :12.

6);; ORNEY Patented 1 943 Bernard Goerg, Bronxville,

. .American Radiator & Standard N. Y., .asslgnor to Sanitary Corporation, New York, N. Y.,. a corporation of 1 Delaware Application July 26, 1941, Serial No. 404,169 12 Claims. 101126-307) My invention relates toheating apparatus such, for example, as furnaces, boilers, and the like, and also to that part of the apparatus which functions to' connect the flue-gas outlets with the chimney or stack and to prevent abnormal changes in chimney draft from having I a harmful effect on combustion conditions.

The invention consists in the novel COIlStI-UG.

tion and combination of parts, to be more fully described hereinafter, and the novelty of which will be particularly pointed out and distinctly claimed.

In the accompanying drawings, to be taken as apart of this specification, I have fully and clearly illustrated two preferred embodiments of my invention, in which drawings- Fig. l is a vertical side elevational view illustrating one preferred embodiment of my invention, with certain of the parts being broken away and others being shown in section for the purposes of clarity;

Fig. 2 is a plan view of the apparatus shown a in Fig. 1, and with certain of the parts being broken away and others being shown in section;

Fig. 3 is an enlarged fragmentary vertical sectional view taken on the line 3-3 of Fig. 2;

Fig. 4 is an exploded view of the back-draft diverter and its chimney connection, with the parts appearing in perspective and certain of the parts being broken away for the purposes of clarity;

Fig. 5 is a fragmentary vertical elevational view showing the end of one of the flue-gas outlet conduits and its connection with the backdraft diverter, the view being on the line 5-5 of Fig. 3;

Fig. 6 is an enlarged fragmentary vertical sectional view, illustrating more clearly the connection between the fiue-gas outlet conduit and the back-draft diverter, the view being taken on the line 56 of Fig. 2;

Fig. 7 is a fragmentary plan sectional view showing my invention as embodied in apparatus of smaller capacity than the apparatus of Figs. 1 to 6 incl.; and

Fig. 8 is an enlarged vertical sectional view taken on the line 88 of Fig. 7.

Referring now in detail to the construction illustrated and first to the construction shown in Figs. 1 to 6 incL, it will be noted that I have shown my invention as embodied in a warm air furnace ill fired by gas. The furnace l G is shown as comprising a furnace casing it having an inlet opening i2 for return air from the rooms to be heated, and a supply or outlet opening i3 through which the heated air flows to the rooms.

The openings l2 and I3 are formed in the 7 horizontal casing top-wall I4 and are arranged in juxtaposed relation to one another, as shown in Figs. 1 and 2. In addition to the top wall M, the furnace casing comprises a horizontal bottom wall l5, vertical side walls l6 and il, vertical end walls 18 and I9, and vertical partition walls 20 and 2|.

The partition wall 2i depends from the top wall M between the openings l2 and i3, and joins the end walls 88 and is along its vertical outer edges and is spaced from the side wall ii and the partition wall 29 to form therewith parallel incoming and outgoing air passages 23 and 24, respectively. The passage 23 is connected at its upper outer end with the inlet open-- ing l2 and the passage 26 at its upper outer end with the air outlet opening H8. The passages are joined at their lower innermost ends by an opening 25 provided in the lower end of the partition wall 21!. v

The partition wall 20 is joined along its outer vertical edges to the end walls l8 and I9 and at its upper and lower ends to the top wall l5 and bottom wall i5, respectively. The partition wall 29 is spaced inwardly from the outer side wall i6 to define a vertical space 25 in which the gas supply pipe and control mechanism may be conveniently located.

The furnace ill also comprises a plurality of separately fired heating units 28 which are identical in construction and which are arranged in uniformly spaced, side-by-side relation across the outgoing passage 2%. Each unit 28 is fired by gas and is provided with its individual gas control valve 29. I have not shown the interior of the combustion chamber or the flue passages of any of the units 23, nor have I shown the gas burner positioned within each combustion chamber, as these details may be of conventional construction.

Each heating unit 28 is provided with an outlet 36 for the flue gases generated therein, and each outlet 30 is arranged so as to discharge the flue gases toward the partition 2i. A plurality of flue-gas outlet conduits 3!, equal in number to the units 28, extend horizontally across the upper end of the passage 23 and are arranged in parallel side-by-side relation, the same as the units 28. Each conduit 3| is provided with an inlet end 32 which extends through an opening in the partition 2| and is joined to an outlet 30 of one of the units 28, and is provided with an outlet end 33 which has a gas tight connecing from the rooms to be top wall units 28.

tion within an opening 34 provided in an inwardly spaced upper part |1a of the side wall l1 (see also Fig. 6)

Flue gases fiowing through the conduits 3|1 heat the latter and consequently, the air returnheated through the opening |2 contacts and absorbs the heat from the exterior surfaces of the outlet conduits 3|. Each conduit 3| may therefore be considered as being an economizer o'r radiator. In certain types of installations, the conduits -or radiators may take the form of straight iron pipes of desired length and diameter. In the construction shown, each radiator is specially constructed so as to provide a relatively high rate ofheat trans'-. fer from the waste fiue gases to the air entering through the opening I2. As shown, each conduit is formed as a one piece casting with internal heat absorbing ribs or fins 35 adapted to contact the flue gases and with external heat radiating and conducting fins 36 adapted to be contacted by the air entering through the opening l2,

In order to provide for the positive flow of air to be heated through the passages 23 and 24 and over the heat-emitting surfaces of the units 28 and the radiators 3|, I provide a motor-driven centrifugal fan 40 positioned within the lower part of passage 23 and having its discharge 4| extending through the opening 25. A suitable air filter 42 is arranged across the incoming pas-, sage 23 and serves to remove foreign particles from the air flowing therethrough.

Na, and l9a, respectively, so as tov provide for natural or gravity circulation of air between the furnace casing and the diverter casing. This circulation of air between adjacent walls will result in the eyaporation or drying up of any condensation which might possibly have occurred in this space due to a leak of flue gas from the The inwardly spaced side wall portion |1a of the furnace casing II is joined to the remaining portions of wall H by a connecting wall portion I117. The two wall portions Ha and |1b provide an outwardly opening recess 44 in the furnace casing II', which extends across the upper edge of the casing It and advantageously receives the outer enclosing casing 45 of a back draft diverter 46.. Wall extensions I81; and |9a of end walls i8 and I9, respectively, close the end of the recess 44, and an extension Ila of 7 l4 covers the top of such recess.

Preferably, the walls defining the recess 44 and casing 45 are of such size and shape that the casing 45 fills neatly the recess 44. The casing 45 comprises an inner side wall 41 positioned parallel to and spaced a slight distance from the inwardly set wall portion |1a, a bottom wall 48 arranged parallel and spaced slightly from the connecting wall portion |1b, atop wall 49 arranged beneath and spaced from an extension Me of the top wall l4, an outer side wall 50' forming an approximate continuation of the outer side wall l1, and end walls 5| and 52 arranged parallel to and spaced inward a slight distance from the end wall extensions |8a and l9a, respectively. The'provision of the recess 44 a and the relationship between its size and shape with that of the casing 45, provide a furnace casing construction which is decidedly. neat and pleasing in appearance and which is, at the same time, highly effective in performing its required function. Even though the inset wall |1a has the effect of narrowing the inlet end of the passage 23, such a. construction does not lower the operating efliciency .of the furnace, because the incoming air is relatively cool and consequently, 'is smaller in volume than after it has passed over the radiators 3| and heating The diverter walls 41, 48,49, 5|, and 52 are preferably spaced from the walls l1a, llb, Ila,

diverter or from the joints between the diverter and conduits 3|. The diverter is rigidly supported in this desired spaced relation with respect to the furnace casing walls by bolts 53 passing through outwardly extending flanges 54 and through end portions of the wall Ho. The flanges 54 extend laterally outward from the vertical inner edges of end walls 5| and 52 and they are set inwardly toward the wall I10. and beyond the wall 41 a sufficient distance to prov de the required spacing between walls I10. and 41.

The wall 41 is provided with a plurality of fluegas inlets 55, equal in number to the heating units 28 and to the flue-gas outlet conduits 3|, and the inlets 55 are so spaced as to receive, respectively, the outlet ends 33 of the conduits 3|. I provide a gas-tight joint between each end 33 and its respective inlet 55 and, at the same time, provide for the tolerances necessary to fit the fixed ends of a plurality of furnace outlet conduits within inlet openings which are preferably formed in the casing wall 41 prior to installation. To this end, 'each inlet 55 is formed larger in diameter than its respective end 33, and the space therebetween is filled by an adapter or filler plate 56 (see Figs. 5 and 6). Each plate 56 is ring-shaped and is provided with a central opening 51 which is of a diameter to receive tightly the end 33 of its respective conduit 3|, and the peripheral portion 58 of each plate 55 slidably fits within an annular recess 59. Each recess 59 is formed by a ring member 60 having an annular outer portion 6| spotwelded to the wall 41 around the opening 55 and having an annular inner portion 62 spaced from the wall 41. The plates 56 are of less diameter than their respective recesses and consequently, each plate may be shifted in a direction normal to the axis of its respective inlet and thereby take care of any misalignment between the conduit ends 33 and their respective inlets 55.

The diverter 45 is provided with an outlet 65 in the outer side wall 50 which is adapted to be connected to the usual chimney, or stack, by an elbow connector 66 secured to the wall 50 about the chimney outlet 65. As can be seen more clearly in Figs. 3 and 4, angle plates 61 and 68 are spot-welded to the wall 50 at the sides and below the outlet 65, respectively. These angle plates provide slots which receive, respectively, flanges 69 and 10 extending laterally from the side and bottom edges of the inlet end of the elbow 66. Thus, the elbow 66 is rigidly held in position on the diverter 46. It is noted that the inlet end of the elbow is higher than the chimneyoutlet 65 and that a portion 1| of the wall 50 extends above the lower part of the inlet end a substantial distance (see particularly Fig.

The wall 50 is provided along the full length of its bottom with an atmospheric outlet 15 which provides open' communication between the interior of the casing 45 and the ambient atmosphere of the basement, or wherever the furnace is in- 2,313,933 stalled. Preferably, the outlet 15 is so located that its upper edge is substantially below the lower edge of the flue-gas inlets 55 so as to prevent flue gases from spilling into the basement during normal operating conditions. This is assured in the relatively large capacity furnace of Figs. 1 to 6 incl. by providing a downwardly directed extension or hood [6 over the outlet 15. Theouter edge 11 of the hood is the eflective upper edge of the outlet 75.

Disposed within the casing 45 and extending from end wall iii to end wall 52 thereof, is a baffle wall 80 which is arranged in a. generally upright position and divides the interior of the casing into an inlet chamber 8| in open communication with the inlets 55 and atmospheric outlet i and into an outlet chamber 82 in open communication with the chimney outlet 65. The upper longitudinal edge of the baflie wall 86 is spaced downwardly from the casing 'top wall 49 to provide an opening 63 connecting the chambers Bi and 82 for the full length of the casing. The baille wall 80 is arranged with its upper edge above the inlets 55 and its lower edge below said inlets so that flue gases entering through the inlets will be intercepted by said baflle. The baille wall 80 is provided in its lower part with a slotlike nozzle passage, or opening, 86 which extends for the full length of the casing and is disposed adjacent to and is directed to discharge chimney back draft toward and through the slot-like atmospheric outlet 75.

In the construction shown, the baffle wall 80 is composed of a plate member 85 so arranged that its two opposite surfaces 86 and 8'! face the flue-gas inlets 55 and the chimney outlet 65, respectively. The plate 85 is inclined upwardly and away from the flue-gas inlets 55 so as to direct the entering flue gas upwardly and through the opening 83 into the'outlet chamber 82 during normal operation; and the plate 85 is also inclined downwardly and away from the chimney outlet 65 so as to direct the flow of back draft from the chimney downward and toward the nozzle passage 84.

The nozzle passage 84 is formed by a plate member 88, and a plate member 89 held in overlapping spaced relation to one another by metal spacing clips 96 which are spot-welded to both plates 88 and 89. The member 88 is shown as being formed as a flange extension of the lower edge of bafile plate 85 and as being inclined in the general direction of the outlet and slightly toward the member 89 so as to direct any back draft against and along the under face of plate member 89. The plate member 89 is shown as being a flange extension of the lower part of plate forming the wall 50 and as extending inwardly and upwardly from the top edge of outlet 15 and as having its inner end portion spaced from and overlying the lower outer edge 9| of the plate member 88 to form the nozzle passage 66.

The upper longitudinal edge of plate member 85 is turned over toward the chimney outlet to provide a curved flange extension 93 of the plate 85 overlying partly the chamber 82. The extension 93 provides a convex upper surface 94 which facilitates the normal flow of flue gas over the top edge of the baiile wall and into the chamber 82 and outlet 65, and also provides a concave under surface 95 which catches any back draft flowing upwardly along the surface 8! and turns such back draft upon itself to form eddy currents and thereby offers an effective obstructio to the flow of back draft through the opening 88 into the inlet chamber 8|.

With a normal chimney condition and normal combustion conditions in the furnace units, the

flue gas will be pulled by the chimney suction through the conduits 3|, the inlets 55 and into the chamber 6i. As the surface 86 is inclined upwardly and away from the inlets 55 and as the flange93 has a convex upper surface 94, the main portion of the flue gas will be deflected by the baflie 3|! to flow through the opening 83 and into the chamber 82 and through the chimney outlet 65 and elbow connection 66 to the chimney. A small amount of the flue gas will be pulled through the opening, or passage, 84 by the chimney draft and also air from the basement will be pulled inward through the outlet 15 and opening 84 into the chamber 82. The full line arrows in Fig; 3 show the direction of flow of flue gas and air under normal operating conditions.

The construction is lower edge 96 of the opening 84 is above the outer edge 71, so that during normal operation, any flue gas that flows downward in the chamber 8i will be pulled into the opening 84 before it can reach the outlet 15 and spill into the basement. The spacing clips are distributed along the slot-like nozzle opening 8 3 in such a manner as to assure the flow of flue part of chamber 8| into the chamber 82, during normal operation. In Fig. 2, four of the clips 90 are shown as being located opposite the chimney outlet 65 and as being in relatively close spaced relation. The purpose of this is to restrict the flow of flue gas through the opening 84 at this point where the suction is greatest and thereby to provide a greater suction along the outer parts of the opening 84 more remote from the outlet 65. Also, two clips 90 are located at the two outer ends of the opening 84 and each of these clips is opposite the space between the end inlet 55 and the inlet adjacent thereto so that a minimum restriction will be offered to the flow of flue gas-from the outer inlets through the opening 84. V

The rate of flow of flue gas is determined by thechimney construction, the rate of combustion taking place in the units 28, and the size of choke plates 91 provided in,the outlet ends 33 of the flue-gas outlet conduits 3 I. The manner in which these fact'o-rs are determined and correlated with respect to one another for any given furnace size and capacity is well known to those skilled in this art and therefore requires no further ex'- planation.

Because of the fact that the atmospheric outlet 15 is in open communication with the inlet chamber 8|, I make possible the practical connection of the flue-gas outlets of a plurality of separate heating units into one inlet chamber or manifold. With such a construction, any abnormal change in flue-gas pressure in any heating unit or its outlet will not harmfully affect the combustion conditions in the other heating units. Should the atmospheric outlet 15 be provided in the outlet chamber 82, instead of the chamber BI, and the outlets of the ing units still be connected to the single chambar 8!, a sudden puiT or like disturbance in one heating unit might increase the pressure in the other units and likely put out the flame therein. The danger of such an efiect would be greater when only the pilot lights are burning in the heating units. In my improved construction any increased gas pressure -caused by a sudden pull or preferably such that the gas in the lower separate heat pressure change in any of the units 28 will be quickly diffused to the atmosphere through the outlet 15 and without any harmful effect on the conditions in any of the other units 28.

In the case of a back draft down the chimney and through the chimney outlet 65, such draft will strike the downwardly inclined face 81 and be directed downward through the nozzle passage 8 3 and readily escape to the atmosphere through the outlet 15 without harmfully affecting the pressure conditions in the chamber 8! and combustion conditions in the units 28. Because of the location and arrangement of the nozzle passage 85 with respect to the chamber 8| and outlet 15, the outward flowing stream of back-draft gas or air through the nozzle M and outlet it will entrain and carry with it any flue gases in the lower part of chamber 81. This action will result in maintaining a pressure condition in the chamber 8| which will permit the continued flow of flue gas into the chamber from the units 28 and thus, prevent a back draft from having a harmful effect upon combustion conditions in the furnace. The dotted line arrows in Fig. 3 illustrate the direction of flow of back-draft gases and flue gases during a back-draft condition. The overhanging concave surface 95 creates eddy currents during a back-draft condition and such currents obstruct the flow of back draft upwardly through the opening B3. Therefore, the pressure of the gas in the outlet chamber 82 is relatively high during a back-draft condition, with the result that the velocity of back draft .through St is high and positive entrainment of the flue gases is effected.

In the construction shown in Figs. 1 to 6 incl. any back draft of chimney gases flowing downward and around the elbow connection 68 will tend to flow to the outside of the curve and will, therefore, strike the bafiie wall Ii, thus, creating eddy currents in the elbow 6B and a substantial obstruction to the back flow of chimney gases before they can enter the chamber 82.

In Figs. '7 and 8, I have shown my invention as embodied in a furnace of relatively small capacity. However, the general construction, operation, and advantages are the same as in the relatively large capacity furnace of Figs. 1 to 6 incl. In

Figs. '7 and 8, only two gas-fired heating units 28a are arranged in the casing lid, and the diverter 66a is of a length to accommodate only we outlet conduits 3la and flue-gas inlets 55a.

The construction of the back-draft diverter is substantially the same as in the previously described modification, except that there is no hood extension to the atmospheric outlet 15a, and the chimney connector 660. is straight and is not of such a size as to provide a baffle wall such as is indicated at H in Fig. 3. The volume of flue gases is smaller in the smaller furnace of Figs. 7 and 8 and hence, the outlet extension 16 is not needed. The edge Ila is beneath the lower edge 9la a suflicient distance so that during normal operation, any flue gas in the lower part of inlet chamber 8la will flow upwardly through nozzle a into outlet chamber 82a and will not spill into the basement through outlet 15a. In Fig. 8, like in Fig. 3, the full line arrows indicate the direction of flue gas and air flow during normal operation and the dotted line arrows indicate the direction of back-draft gases and flue gas dur- Tag a back-draft condition.

What I claim and desire to secure by Letters Patent of the United States is:

1. A back-draft diverter comprising a hollow casing having an inlet for flue gases through one side thereof and a chimney outlet through the opposite side thereof and having an atmospheric outlet through the lower part thereof; a baiile arranged in a generally upright position within said casing and between said flue-gas inlet and chimney outlet to provide at one side thereof an inlet chamber in open communication with said flue-gas inlet and with said atmospheric outlet, and to provide at the other side thereof an outlet chamber in open communication with said chimney outlet; said baffle being spaced from the lower portion of the casing to provide a discharge opening at the lower part thereof adjacent and communicating with-said atmospheric outlet, and said baffle being spaced from the upper portion of the casing to provide an opening at the top of said baffle connecting said inlet and outlet chambers, and the surface of said baflie facing said flue-gas inlet being inclined upward and away from said flue-gas inlet and the surface of said baiile facing said chimney outlet being inclined downward and away from said outlet and toward said discharge opening so that during normal operation flue gas entering the casing through said inlet is directed upward and through the opening at the top of the baffle and into the outlet chamber, and so that back draft through said chimney outlet will be directed downward and through said discharge opening.

2. A back-draft diverter comprising a hollow casing having an inlet for flue gases through one side thereof and a chimney outlet through the opposite side thereof and having an atmospheric outlet through the lower part thereof; a baffle arranged in a generally upright position within said casing and between said flue-gas inlet and chimney outlet to provide at one side thereof an inlet chamber in open communication with said fluegas inlet and atmospheric outlet, and to provide at the other side thereof an outlet chamber in open communication with said chimney outlet; said baffle being constructed and arranged to provide an opening at its lower portion through which any back draft may be discharged from said outlet chamber to the atmosphere; and said bailie havin an upper edge spaced downward from the top of said casing to provide communication be-- tween said chambers, and having a surface facing said inlet and inclined upward and away from said inlet to facilitate normal flow of flue gas over said upper edge, and having a surface facing said chimney outlet and inclined downward and away from said outlet to facilitate flow of back draft downward through said discharge opening to the atmosphere; and the upper edge of said baiiie being turned over and toward said chimney outlet to provide a flange overhanging said outlet chamber.

3. A back-draft diverter comprising'a hollow casing having an inlet for flue gases through one side thereof and a chimney outlet through the opposite side thereof and having an atmospheric outlet through the lower part thereof; a baffle arranged within said casing between said flue-gas inlet and chimney outlet to provide at one side thereof an inlet chamber in open communication with said flue-gas inlet and atmospheric outlet, and to provide at the other side thereof an outlet chamber in open communication with said chimney outlet; said baffle including a first plate so arranged that its two opposite sides face said inlet and said chimney outlet, respectively, and said plate being inclined upward and away from said inlet and downward and away from said chimney outlet and having a top edge spaced downward from the top 'of-said casing toprovide communication between said chambers, and said baflle including a second plate extending from the 'asiaejas :fpart thereof,-'andproviding a nozzle opening cone i 1 v -necting said chambers at the lower part thereof 7 andthe latter opening being directe to dischar e lower partfofsaid first plate toward said atmospheric outlet and a thirdplate extending inward I from said casing at regions adjacent said atmospheric outlet and arranged in overlying spaced through said flrstopening and into said outlet.

relation'with respectto the outer portions of said through the lower part thereof; bathe means dividing the interior of said casing into an inlet chamber in open communication with said inlet and said atmospheric outlet and into an outlet chamber in open communication with said chimney outlet; said bafiie means being spaced from said casing to provide a first opening connecting said chambers at the upper part thereof and said bafile means having means associated with the lower portion thereof to provide a nozzle opening communicatively connecting said chambers at the lower part thereof and the nozzle opening having its discharge end directed to discharge backdraft toward said atmospheric outlet; and said bafie means including means providing for directing the normal in-flow of flue gases upward and through said first opening and into said outlet chamber, and for obstructing the fiow of back draft through said first opening and for directing such back draf t downward through said nozzle opening.

5. A back-draft diverter comprising a hollow casing having an inlet for flue gases through one side thereof and a chimney outlet through the opposite side thereof and an atmospheric outlet through the lower part thereof; baifie means dividing the interior of said casing into an inlet chamber in open communication with said inlet and said atmospheric outlet and into an outlet chamber in open communication with said chimney outlet; said baflie means being spaced from said casing to provide a first opening connecting said chambers at the upper part thereof and said bailie means having means associated with the lower portion thereof to provide a nozzle opening connecting said chambers at the lower part thereof and the nozzle opening being directed to discharge toward said atmospheric outlet; and said baiiie means including means providing for directing the normal in-fiow of flue gascs'upward and through said first opening and into said outlet chamber, and providing for obstructing the flow of back draft through said first opening and for directing such back draft downward through said toward said atmosphericoutlet; and said baflie means includingrneans providing for-directing the normal ineflow of flue gases upward and chamber, and providing for obstructing the flow of back draft through said firstopening and for directing such back draft downwardthrough said nozzle opening; said last-named means including a platearranged with its two opposite surfaces facing generally said inlet and said chimney outlet, respectively, and said plate being inclined upward and away from said inlet and downward and away from said chimney outlet; and the top edge of said plate defining the bottom of said first opening and being formed as a flange member extending from the main body of said plate partly over said outlet chamber.

7. A back-draft diverter comprising a hollow f casing having an inlet for flue gases through one nozzle opening; said last-named means including v a plate arranged with its two opposite surfaces facing generally said inlet and said chimney outlet, respectively, and said plate being inclined upward and away from said inlet and downward and away from said chimney outlet.

6. A back-draft diverter comprising a hollow casing having an inlet for flue gases through one side thereof and a chimney outlet through the opposite side thereof and an atmospheric outlet side thereof,

side thereof and a chimney outlet through the opposite side thereof and an atmospheric outlet through the lower part thereof; bafi'ie means dividing the interior of said casing into an inlet chamber in open communication with said inlet and said atmospheric outlet and into an outlet chamber in open communication with said chimney outlet; said bafiie means providing a first opening connecting said chambers at the upper part thereof, and providing a nozzle opening connecting saidchambers at the lower part thereof and the latter opening being directed to dischargeltoward said atmospheric outlet; and said bafiie means including means providing for directing the normal in-fiow of flue gases upward and through said first opening and into said outlet chamber, and providing for obstructing the flow of back draft through said first opening and for directing such back draft downward through said nozzle opening; said last-named means including a plate arranged with its two opposite surfaces facing generally said inlet and said chimney outlet, respectively, and said plate being inclined upward and away from said inlet and downward and away from said chimney outlet, and the top edge of said plate defining thebottom of said first opening and being. formed with an upwardly facing convex surface to facilitate the flow of flue gases thereover.

8. A back-draft diverter comprising a hollow casing having a flue-gas inlet through one side thereof, a chimney outlet through the opposite and an atmospheric outlet through the lower part thereof; baiile means dividing the interior of said easing into an inlet chamber in open communication with said inlet and said atmospheric outlet and into an outlet chamber in open communication with said chimney outlet and said bafiie means being constructed to provide a first opening at the top thereof connecting said chambers and to provide adischarge opening at the bottom thereof and adjacent said atmospheric outlet; and said bafiie means including a surface facing said chimney outlet and a flange member projecting from said surface beneath said first connecting opening and in a direction to partially overlie said outlet an obstruction on said surface to the up-fiow of back'drait through said first connecting opening.

9 A back-draft diverter comprising a hollow casing having a flue-gas inlet through one side thereof, a chimney outlet through the opposite side thereof, and an atmospheric outlet through chamber and thereby offering the lower part thereof; baille means dividing the interior of said casing into an inlet chamber in open communicationwithsaid inlet and said atmospheric outlet and into an outlet chamber in open communication with said chimney outlet and said baflle means constructed to provide a discharge opening at the bottom thereof adjacent said atmospheric outlet and including a plate member arranged with its opposite surfaces facing said inlet and chimney outlet, respectively,

and said plate having a top edge spaced downward from the casing top to provide a second opening connecting said chambers and through which flue gases normally flow into said outlet chamber; and a flange member extending along the top of said plate beneath said second opening and partially overlying said outlet chamber to offer an obstruction to the up-flow of back draft along said plate and through said second connecting opening.

10. A back-draft diverter comprising a hollow casing having a flue-gas inlet through one side thereof, a chimney outlet through the opposite side thereof, and an atmospheric outlet through the lower part thereof; baiiie means dividing the interior of said easing into an inlet chamber in open communication with said inlet-and said atmospheric outlet and into an outlet chamber in open communication with said chimney outlet and said baflie means'constructed to provide a discharge opening at the bottom thereof adjacent said atmospheric outlet and including a plate member arranged with its'opposite surfaces facing said inlet and chimney outlet, respectively, and said plate having atop edge spaced downward from the casing top to provide a second opening connecting said chambers and through which flue gasesnormaily flow into said outlet chamber; and a flange member extending along the top edge of said plate and projecting from said plate partially over said outlet chamber to offer an obstruction to the up-flow of back draft along said plate and through said second connecting opening and said flange member being formedwith a convex upper surface to facilitate the normal flow of flue gases into .said outlet chamber.

11. A back-draft diverter comprising a hollow casinghaving a flue-gas inlet through one side thereof, a chimney outlet through the opposite side thereof, and an atmospheric outlet through the lower part thereof; baffle means dividing the interior of said casing into an inlet chamber in open communication with said inlet and said atmospheric outlet and into an outlet chamber in open communication with said chimney outlet and said bafile means constructed to provide a discharge opening at the bottom thereof adJacent said atmospheric outlet and including a plate member arrangedwith its opposite surfaces facing said inlet and chimney outlet, respectively, and said plate having a top edge spaced downward from the casing top to provide a second opening connecting said chambers and through which flue gases normally flow into said outlet chamber; and said top edge of said plate being formed with a turned over flange partially overlying said outlet chamber and providing a convex upper surface to facilitate the normal flow of flue gases thereover and a concave under surface to obstruct upflow of back draft.

12. A back-draft diverter comprising a casing including top, bottom, side, and end walls; said casing having a plurality of flue-gas inlets through one side wall thereof, a chimney outlet in the opposite side wall thereof, and having a slot-like atmospheric outlet in the lower part of said casing and extending for substantially the length of the casing; a battle wall extending between the end walls for substantially the length of said casing and dividing the interior into an inlet chamber in open communication with said inlets and said atmospheric outlet and into an outlet chamber in open communication with said chimney outlet, and said baffle wall being constructed to provide a first opening extending for the length of said casing and connecting said chambers across the casing top and through which flue gas normally flows into said outlet chamber; means forming a slot-like nozzle passage located at the lower portion of said battle and extending for substantially the length of said opening.

casing, the discharge end of said nozzle passage being directed toward said atmospheric outlet; and said bafile wall including means facilitating normal flow of flue gas through said connecting opening and into said outlet chamber and for obstructing the flow of back draft through said BERNARD GOERLG. 

